Exfoliated metal free homojunction photocatalyst prepared by a biomediated route for enhanced hydrogen evolution and Rhodamine B degradation†
g-C3N4 has been widely used as a smart material for photocatalytic applications. Due to insufficient solar-light absorption and fast electron–hole recombination, the photocatalytic activity of g-C3N4 remains a challenge for industrial applications. In this study, we prepared an exfoliated g-C3N4 homojunction in a single-step biomediated route, thereby addressing the major issues of g-C3N4. With a well exfoliated and layered sheet structure, g-C3N4 exhibits exceptional physical properties such as ultrahigh intrinsic carrier mobility and pronounced changes in the energy band structure due to weak van der Waals forces between C3N4 layers. The formation of well exfoliated sheets of g-C3N4 was confirmed by XRD, FESEM, TEM and AFM results. More importantly XPS confirmed the synthetic process by the biomediated route, in which some electron acceptor (–CN) groups were easily introduced at the edge of g-C3N4, aiding the in situ p–n homo-junction formation. The g-C3N4 homojunction was confirmed by Mott–Schottky analysis. This homojunction structure was proven by EIS and TRPL analysis to be highly proficient in charge transfer and separation processes. The exfoliated g-C3N4 homojunction showed significantly enhanced photocatalytic activity, compared to that prepared through the conventional route, due to the unique structural advantages, electron transfer, light harvesting, lower recombination rate of charge carriers and the richly available reaction sites during the photocatalytic reaction. g-C3N4 prepared through the one step biomediated route was able to evolve 87 μmol h−1 of H2 and degrade 90.2% of 200 ppm RhB solution, which is significantly higher than bulk g-C3N4 prepared through the conventional route.